Nesting Habits of Some Hornet Species (Hymenoptera, Vespidae) in Northern Thailand

Kasetsart J. (Nat. Sci.) 38 : 196-206 (2004) Nesting Habits of Some Hornet Species (Hymenoptera, Vespidae) in Northern Thailand Masao Nakamura 1 and Saowapa Sonthichai 2 ABSTRACT Seven nests of four hornet (Vespa) species collected around Chiang Mai, northern Thailand were described. Species observed were: V. affinis (2 nests), V. mocsaryana (2), V. velutina (2), and V. tropica (1). Three species coexisted on the Campus of Chiang Mai University. First reliable record of the colony composition of V. mocsaryana was presented. All the nests had only one foundress queen in July/August (mid- to late polyethic stage). Key words: Vespa spp, nesting sites, Vespidae INTRODUCTION The vespid genus Vespa (hornets) is principally Oriental and eastern Palearctic in distribution, and has the largest number of species in hilly and montane regions in tropics and subtropics from eastern Himalaya through Myanmar and Thailand to southern China (van der Vecht, 1957, 1959; Matsuura and Yamane, 1990; Carpenter and Kojima, 1997). The highest diversity in the nesting habit of hornets is also anticipated in this region (Nguyen and Carpenter, 2002), but information on their biology is quite restricted. Nesting biology of some hornet species around Chiang Mai, northern Thailand during late July and early August in 2001 were studied. Seven nests of four species of Vespa were collected and their nesting characteristics were observed and recorded. MATERIALS AND METHODS Study sites and methods Chiang Mai is located at ca. 18 N and has a tropical monsoon climate, with relatively distinct rainy and dry seasons. The material was collected in the rainy season. The Campus of Chiang Mai University, where most of the nests were located, was 315 m in altitude, while a Karen village, Mae Wang, where a nest of V. tropica was located, was around 1,000 m in altitude. Hornet nests found on trees and buildings and underground were recorded and photographed, then collected using an anesthetic, an insecticide sprayer and protective suits after stuffing cotton in nest entrances. Returning wasps were netted for one hour after nest collection. Collected nests were carried to the room and cell maps (Yamane and Yamane, 1975) were taken to record colony contents. Identification of species was made, and the results were checked by Prof. Seiki Yamane of Kagoshima University. 1 Shinsakuragaoka 1-19-5, Hodogaya-ku, Yokohama-shi, 240-0036 Japan. 2 Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand. Received date : 13/02/04 Accepted date : 31/03/04

Kasetsart J. (Nat. Sci.) 38 (2) 197 RESULTS Nesting sites Nesting sites of the collected colonies are given in Tables 1 (A-G) together with other biological information. All nests (two) of V. affinis (TH01-MN-01, -02) (Figure 1d, 1f) and two of V. mocsaryana (-03, 04) (Figure 1a, 1c) were found in the open sites. Both branch and structural nestings were recognized in these species. One of the nests of V. mocsaryana (-04) (Figure 1a) was located in a hidden site in a bamboo bush close to the ground. The two V. velutina nests (-05, -06) were made under the eaves of university buildings (Figure 1b, 1e). The single nest of V. tropica (-07) was found in soil of a rocky slope. In Chiang Mai University campus four nests of three species were collected. The bigger of the two nests of V. affinis was only 60 m apart from a nest of V. velutina, and the distance between the two V. velutina nests was 80 m. The single nest of V. mocsaryana (-03) and the two nests of V. velutina found on the university campus had no trace of structure constructed by the foundress, thus were suspected of having moved from the original place (nest relocation sensu by Matsuura, 1984 and Matsuura and Yamane 1990; or translocation of nest sensu by Edwards, 1980). No information was obtained on the original nesting sites of these species. Nests of two other species, V. mandarinia and V. soror, were sold at the markets around Chiang Mai, but their origins (nesting sites) were not traced. Nest structure Structure of envelope and comb in the four species was summarized in Table 2. Several types of envelope were recognized. In V. affinis and V. velutina the envelope was composed of shells, giving a scalloped pattern. However, in the latter shells were larger and less defined or wider than in the former. In both species the envelope was approximately 4.5 cm thick. The V. mocsaryana nests had an envelope composed of longitudinal wide tunnels rather than shells, and was only 1.5 cm thick. The single underground nest of V. tropica was damaged when collected, and the size could not be measured; the envelope was like a cylinder made of sheets of waving paper and without distinct shells. In terms of the number of combs and comb size V. affinis constructed the largest nests, while V. tropica did the smallest. But in the number of cells V. velutina rivalled V. affinis. Colony composition Colony composition of the seven nests was given in Table 1 (A-F). In all the nests the founding queen was still alive; polygyny was not seen. In the foundress of V. tropica the wings were almost worn out and the body shined black. The number of workers was large in V. affinis and V. velutina (1381-1457), while less than 300 were present in the nests of V. mocsaryana and V. tropica. A clear relation was seen between the numbers of workers and cells. From a nest of V. affinis a male and a new queen were collected, and in a nest of V. mocsaryana a male was seen. In the three species (excluding V. tropica), the first comb (sometimes also second) almost ceased to be used with few eggs and young larvae. In V. tropica, however, the first comb was still being used to rear young, the numbers of eggs and young larvae matching those in the second comb. DISCUSSION The Campus of the Chiang Mai University has an area of only approximately 2.9 km 2, but harbours at least three species of hornet. Although the number represented only minor part of the whole hornet fauna in Thailand (13 species; Carpenter and Kojima, 1997), the fact that three predaceous species with similar nesting sites coexisted in a small area might give one of the

198 Kasetsart J. (Nat. Sci.) 38 (2) Table 1 Colony composition of the collected nests. 1-A. Vespa affinis: TH01-MN-01 (on a bamboo stem, at 1.5 m above ground; Mae Wang suburbs of Chiang Mai). 1 20.0 18.0 5 5 2 0 0 0 2 458 472 2 25.0 19.0 92 14 19 5 2 5 5 447 586 3 25.0 23.5 138 28 42 70 25 26 58 304 701 4 28.0 24.5 238 74 61 74 27 38 69 298 879 5 32.5 27.0 382 98 68 194 72 64 104 142 1124 6 40.5 32.0 628(5)* 179 234 426 119 124 256 64 1958 7 35.0 28.5 473(16) 77 136 305 83 91 211 12 1376 8 24.0 20.5 17(2) 25 47 181 91 70 125 7 563 Total 1968(23) 500 609 1255 328 425 830 1732 7647 Adults. Foundress: 1, females: 1376, males: 3, new queen: 1 Numerals in parentheses: no. new queens

Kasetsart J. (Nat. Sci.) 38 (2) 199 1-B. Vespa affinis: TH01-MN-02 (on the window frame; Campus of Chiang Mai Univ.). 1 7.5 7.0 1 0 0 0 0 0 0 103 104 2 13.0 8.0 25 0 0 0 0 0 0 98 125 3 20.0 14.0 84 27 36 8 5 4 36 170 370 4 25.0 13.0 112 26 43 18 14 10 43 119 385 5 28.0 13.0 141 58 31 23 12 13 96 107 481 6 30.0 17.0 202 73 34 21 10 15 125 190 670 7 28.0 15.0 111 71 35 18 12 33 94 61 454 8 20.0 11.0 51 42 36 38 18 27 51 30 301 9 6.0 5.0 0 0 0 0 0 1 12 28 41 Total 727 297 215 126 71 103 457 906 2913 Adults. Foundress: 1, females: 486, males: 0, new queen: 0

200 Kasetsart J. (Nat. Sci.) 38 (2) 1-C. Vespa mocsaryana: TH01-MN-03 (on the ceilings of a building; Campus of Chiang Mai Univ.). 1 8.0 7.0 30 10 9 6 5 3 7 0 70 2 12.0 12.0 116 50 21 19 16 11 52 0 285 3 13.5 13.5 129 70 42 41 18 20 69 0 389 4 10.0 10.0 64 30 30 27 20 20 25 3 219 Total 339 160 102 93 59 54 153 3 963 Adults. Foundress: 1, females: 230, males: 0, new queen: 0 1-D. Vespa mocsaryana: TH01-MN-04 (in bamboo bush, at 1.0 m above ground; Tha Tarn; suburbs of Chiang Mai). 1 12.5 11.0 86 28 21 18 13 12 32 25 235 2 15.5 15.0 135 49 45 34 33 25 90 3 414 3 16.5 15.0 178 56 49 51 27 38 130 2 531 4 7.5 7.5 0 19 19 14 25 28 36 1 95 Total 399 138 134 117 98 103 288 31 1275 Adults. Foundress: 1, females: 299, male: 1, new queen: 0

Kasetsart J. (Nat. Sci.) 38 (2) 201 1-E. Vespa velutina: TH01-MN-05 (under the cases of a building; Campus of Chiang Mai Univ.). 1 26.0 24.0 300 20 10 5 5 2 3 393 738 2 28.0 26.0 375 75 64 80 40 28 76 219 957 3 33.0 31.0 342 308 138 112 106 118 209 138 1471 4 33.0 32.0 710 166 107 186 112 96 144 93 1614 5 26.0 25.0 350 169 137 196 140 154 179 36 1361 6 8.0 7.0 0 0 2 5 13 20 48 8 96 Total 2077 738 458 584 416 418 659 887 6237 Adults. Foundress: 1, females: 1456, male: 0, new queen: 0 1-F. Vespa velutina: TH01-MN-06 (on ceilings of a building; Campus of Chiang Mai Univ.). 1 20.0 19.0 244 16 8 2 0 0 0 214 484 2 23.0 21.0 464 96 56 64 30 28 58 94 890 3 25.0 20.0 324 214 52 56 36 18 132 32 864 4 23.0 23.0 340 174 110 163 106 90 252 11 1246 5 19.5 16.0 111 162 56 58 50 38 168 5 648 6 13.0 10.0 0 0 0 24 18 19 33 2 96 Total 1483 662 282 367 240 193 643 358 4228 Adults. Foundress: 1, females: 802, male: 0, new queen: 0

202 Kasetsart J. (Nat. Sci.) 38 (2) 1-G. Vespa tropica: TH01-MN-07 (the underground, Tha Tarn; the suburbs of Chiang Mai). 1 22.0 19.0 106 42 34 25 20 12 75 25 339 2 19.0 18.0 80 41 33 26 15 16 61 22 294 3 7.0 6.5 15 14 3 5 2 4 10 3 56 Total 201 97 70 56 37 32 146 50 689 Adults. Foundress: 1, females: 147, male: 0, new queen: 0 reasons for a rich hornet fauna in Thailand. In the Ryukyu Islands, Japan competitive exclusion of hornet species among islands has been implied (Yamane, 1988). Additional information on food preference in the three Vespa species and prey biomass around Chiang Mai should be collected. Nesting sites in the four species well agreed with those reported previously, though information on the nesting habits of V. mocsaryana was almost lacking. For example, V. affinis has been known to construct nests in open spaces (mainly on small trees or in bushes) in subtropical Japan (Martin, 1992), Taiwan (Yamane, 1977), Sulawesi (Kojima et al., 2001), Sumatra (Matsuura, 1990), and India (Das and Gupta, 1989). In the present survey one nest was found on a window frame of a building. Matsuura (1990) also reported that in Sumatra seven of the 214 collected nests of this species were nesting on exposed sites of buildings (another 17 nests were found from attics). V. velutina constructs nests on the branch of big trees (but occasionally in bushes and in buildings) in Taiwan (Yamane, 1977). V. tropica is generally an underground nester, structural nests being rarely found in Sumatra (Matsuura, 1990). Archer (1997) mentioned that almost nothing was known of the nesting habits of V. mocsaryana. Some nests of V. velutina and V. mocsaryana were found with no trace of initial nest structure retained. This suggested a high probability that these nests were relocated in open locations after moving from original sites. The nest relocation has been frequently observed in some Japanese species such as V. simillima, V. crabro and V. dybowskii (Makino et al., 1981; Matsuura, 1995). Species constructing large nests may tend to move from covered sites for initial nests to exposed sites with colony growth, though in Thailand no information is available on the site of initial (embryo) nests in Vespa. The pattern of envelope varied from species to species, but it was not evident that this character had any phylogenetic implication. A difference in

Kasetsart J. (Nat. Sci.) 38 (2) 203 a b c d e f Figure 1 Nests of Vespa spp. a. V. mocsaryana b. V. velutina c. V. mocsaryana d. V. affinis e. V. velutina f. V. affinis

204 Kasetsart J. (Nat. Sci.) 38 (2) Table 2 Nest structure of collected hornet species. No. of Diameter of Nest Envelope Direction Nesting type no. cells largest diameter pattern of entrance comb (cm) incl. envelope (cm) V. affinis 8 7648 32.0 40.5 55.0 Scalloped North Open site (TH01-MN-01) V. affinis 9 2913 17.0 30.0 48.0 Scalloped Northeast Open site (TH01-MN-02) V. mocsaryana 4 963 13.5 18.0 Tunneled East Open site (TH01-MN-03) V. mocsaryana 4 1275 15.0 16.5 23.0 Tunneled East Open site (TH01-MN-04) V. velutina 6 6237 32.0 33.0 51.0 Scalloped East Open site (TH01-MN-05) V. velutina 6 4228 33.0 37.0 Scalloped East Open site (TH01-MN-06) V. tropica 3 147 19.0 22.0 33.5 Sheet-like West Covered site (TH01-MN-07) envelope pattern was recognized between V. velutina and V. mocsaryana which were considered to form a monophyletic group by Archer (1994, 1997). More information across all the vespine species and their geographical races. Judging from colony composition, most of the nests examined in this study were thought to be at mid- to late polyethic stages (Matsuura and Yamane, 1990). Therefore, the colony size among the species could not be compared. For example, the two nests of V. velutina examined were in some parameters smaller than those of V. affinis. V. velutina is, however, known to construct huge nests in Taiwan with the maximal number of cells attaining 20,000 (Yamane, 1977, 1992), while the biggest nests of V. affinis there has had only 6,178 cells (Matsuura, 1973). Although in tropical areas V. affinis might construct much larger nests (15,065 cells in Papua New Guinea recorded by Spradbery, 1986; 14,000 in the Philippines reported by Starr and Jacobson, 1990), in this species the colony life span tended to be shorter and colony size smaller than in sympatric populations of V. velutina. The presence of only one foundress in each colony does not necessarily indicated the haplometrotic colony foundation. Matsuura (1990) reported that in Sumatra approximately 80% of the initial colonies of V. affinis were pleometrotic in colony foundation; the number of foundress ranged between 1 and 14, and in some nests multiple queens remained into the mature stage (Martin, 1995). Multiple-queen colonies in northern Thailand were not witnessed, though only a few colonies were examined for each species. In spite of the rich species diversity of Vespa (13 species) in Thailand only scanty information has been available. Even the distribution range for each species is not known in detail. It is hope that this report will stimulate Thai entomologists to intensively study this ecologically

Kasetsart J. (Nat. Sci.) 38 (2) 205 and economically important group of wasp. CONCLUSION Considering the short survey period and small area surveyed, the number of species (4) collected indicated that northern Thailand seemed to harbour a rich hornet fauna. Nests of three species (V. affinis, V. mocsaryana and V. velutina) were found in the open sites, while the single nest of V. tropica was underground. Nest relocation was suspected for V. velutina and V. mocsaryana. In the enveloped pattern, different types were recognized among species, though V. affinis and V. velutina had similar scalloped patterns. ACKNOWLEDGEMENTS We would like to thank Prof. Seiki Yamane of Kagoshima University for his reading through the earlier drafts of the manuscript and identification of the wasps. LITERATURE CITED Archer, M.E. 1994. A phylogenetic study of the species of the genus Vespa (Hymenoptera: Vespinae). Entomologica Scandinavica 24: 469-478. Archer, M.E. 1997. Taxonomy, distribution and nesting biology of Vespa affinis (L.) and Vespa mocsaryana du Buysson (Hym., Vespinae). Entomologist s Monthly Magazine 133: 27-38. Carpenter, J.M. and J. Kojima. 1997. Checklist of the species in the subfamily Vespinae (Insecta: Hymenoptera: Vespidae). Natural History Bulletin of Ibaraki University 1: 51-92. Das, B.P. and V.K. Gupta. 1989. The Social Wasps of India and the Adjacent Countries. The Association for the Study of Oriental Insects, Gainesville. 292 p. Edwards, R. 1980. Social Wasps: Their Biology and Control. Rentokil Ltd., East Grinstead. 398 p. Kojima, J., Sri Hartini, Woro Noerdjito, Sih Kahono, N. Fujiyama and H. Katakura. 2001. Descriptions of pre-emergance nests and mature larvae of Vespa fervida, with a note on a multiple-foundress colony of V. affinis in Sulawesi (Hymenoptera: Vespidae; Vespinae). Entomological Science 4: 355-360. Makino, S., Sk. Yamane, T. Ban and I. Kunou. 1981. The Japanese hornet Vespa simillima Smith, an important nuisance pest in urban areas (Hymenoptera: Vespidae). Japanese Journal of Sanitary Zoology 32: 203-213. Martin, S.J. 1992. Development of the embryo nest of Vespa affinis (Hymenoptera: Vespidae) in Southern Japan. Insectes Sociaux 39: 45-57. Martin, S.J. 1995. Comparison of tropical and subtropical colonies of the hornet Vespa affinis. Asian Journal of Tropical Biology 1: 11-17. Matsuura, M. 1973. Nesting habits of several species of the genus Vespa in Formosa. Kontyu 41:286-293. Matsuura, M. 1984. Comparative biology of the five Japanese species of the genus Vespa (Hymenoptera, Vespidae). Bulletin of the Faculty of Agriculture, Mie University 69: 1-131. Matsuura, M. 1990. Biology of three Vespa species in Central Sumatra (Hymenoptera, Vespidae), pp. 113-124. In S.F. Sakagami, R. Ohgushi and D.W. Roubik (eds.). Natural History of Social Wasps and Bees in Equatorial Sumatra, Hokkaido University Press, Sapporo. Matsuura, M. 1995. Social Wasps of Japan in Color. Hokkaido University Press, Sapporo. 353 p. (In Japanese with English Summary.) Matsuura, M. and Sk. Yamane. 1990. Biology of the Vespine Wasps. Springer-Verlag, Berlin. xix+323 p.

206 Kasetsart J. (Nat. Sci.) 38 (2) Nguyen, T.P.L and J.M. Carpenter. 2002. Vespidae of Vietnam (Insecta: Hymenoptera) 1. Vespinae. Journal of New York Entomological Society 110: 199-211. Spradbery, J.P. 1986. Polygyny in the Vespinae with special reference to the hornet Vespa affinis picea Buysson (Hymenoptera: Vespidae) in New Guinea. Monitore Zoologico Italiano (N.S.) 20: 101-118. Starr, C.K. and R.S. Jacobson. 1990. Nest structure in Philippine hornets (Hymenoptera: Vespidae, Vespa spp.). Japanese Journal of Entomology 58: 125-143. Yamane, Sk. 1988. Hornet fauna of the Ryukyu Archipelago. Japan. Satsuma 100: 161-174. (In Japanese.) Yamane, So. 1977. On the collecting technique of vespine nests, based chiefly on practices through a survey in Taiwan from 1972 to 1974 (Hymenoptera, Vespidae). Seibutsukyozai 12: 42-59. (In Japanese.) Yamane, So. 1992. A huge nest of Vespa basalis in Taiwan (Hymenoptera: Vespidae). Chinese Journal of Entomology 12: 1-11. Yamane, So. and Sk. Yamane. 1975. Investigation methods of dead vespine nests (Hymenoptera, Vespidae). Seibutsu-kyozai 10: 18-39. (In Japanese.) van der Vecht, J. 1957. The Vespinae of the Indo- Malayan and Papuan Areas (Hymenoptera, Vespidae). Zoologische Verhandelingen vor Rijksmuseum van Natuurlijke Historie, Leiden 34: 1-83, 6 pls. van der Vecht, J. 1959. Notes on Oriental Vespinae, including some species from China and japan (Hymenoptera, Vespidae). Zoologische Mededelingen 13: 205-232.